1. Field of the Invention
The present invention relates generally to a defect information managing method, and more particularly, to a defect information managing method for protecting and managing information when a defect exists on a storage media.
2. Description of the Background Art
FIG. 1 is an illustration showing a track structure for a storage media of the storage device which is a background of the present invention. In FIG. 1, a storage media 10 is provided with a defect information block 11, an alternate area 12, and a user area 13 in that order, for example, from an inside track to an outside track. Information concerning a defect on a storage media is stored in each track of the defect information block 11. The information concerning a defect includes, for example, information indicating which track is defective. A defective portion of the user area 13 is replaced with the alternate area 12, in which information in the defective portion is stored. In the storage device 10, the defective portion of the track in the user area 13 is replaced with the alternate area 12 based on the information stored in the defect information block 11, so that the reliability is improved.
Meanwhile, if and when digital information is written onto a magnetic disk such as a hard disk or a floppy disk, the information is stored by completely inverting the magnetization corresponding to binary information, so that new information can be overwritten on old information without erasing the old information. However, in the case of a magneto-optic disk, the old information must be erased once before writing. Therefore, in the magneto-optic disk, if an accident such as instantaneous power failure occurs when the information concerning a defect in the above described defect information block 11 is updated, the defect information on the disk is destroyed. Thus, in the worst case, the entire system can not be utilized. In addition, if the information concerning a defect has been erased, it is liable to be erroneously recognized that no information concerning a defect is registered.